1. Field of the Invention
The present invention generally relates to engine leak testing and, more specifically, toward, a method for pressure testing engines.
2. Description of Related Art
During the manufacture of engines, it is desirable to test the assembled engine to determine if any of the various oil seals are leaking. Such leaks can occur due to assembly errors, damaged seals, or contamination of the sealing surfaces. However, due to the construction of modern engines, it has proven difficult to develop engine leak testing methods that can be employed quickly, as is required for manufacturing efficiency.
One problem encountered in developing effective leak tests is that there are numerous places to which pressurized air may be applied to an engine, and a similar number of areas that air will flow out of a pressurized engine. Air can be applied to the intake manifold, the exhaust manifolds, the engine oil fill, and one or more ports on the head cover. Air can also leak out of a pressurized engine at the intake manifold, the exhaust manifolds, and the exhaust gas recirculation valve.
One known testing method that has been employed in the past involves introducing pressurized air through one of the head covers, and then measuring the flow rate of pressurized air through the engine. In this method, the pressurized air exits the engine via the intake and exhaust manifolds, and this rate of flow is used as a baseline to determine whether the engine is leaking at other locations. However, it has been found that the flow rate through the engine is so great that it masks any leaks that may occur. Accordingly, the known testing method is not sensitive enough to reliably detect engine oil leaks.
Therefore, there exists a need in the art for a method to test an engine for potential oil leaks.